1. Field of the Invention
The present invention relates to a camera having a picture-taking optical system and an optical finder including a finder optical system favorable for the camera.
2. Description of the Related Art
It is generally desired that cameras, especially electronic cameras be thinned. To achieve a thin electronic camera, it has recently been proposed that the camera be equipped with a so-called optical-axis bending type picture-taking optical system. This type of picture-taking optical system is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 11-196303. As is described in this publication, the picture-taking optical system includes a reflection plane, on which a picture-taking optical axis is bent and its direction made coincident with the width direction of the camera, thereby reducing thickness of the camera.
Cameras require a finder. The finder aims at observing an image of an object to be photographed and generally an optical finder is used as such a finder. Electronic cameras usually include an LCD (liquid crystal display) to allow the image of an object to be observed. In view of power savings, however, most electronic cameras are so configured that an optical finder is used for taking a picture of an object and an LCD is used only for reproducing the picture for observation.
Cameras also require a zoom mechanism. The zoom mechanism is designed to continuously vary focal length, usually by moving a zoom lens in the direction of an optical axis. If a picture-taking optical system is to include a zoom mechanism, its corresponding optical finder also needs a zoom mechanism. These zoom mechanisms have to be interlocked with each other. Jpn. Pat. Appln. KOKAI Publications Nos. 2000-147606 and 2001-133850 disclose a camera that is so configured that the zoom ratio of a finder optical system varies with that of a picture taking optical system.
To incorporate an optical-axis bending type picture-taking optical system allows a picture-taking lens unit to be thinned. However, such an optical-axis bending type picture-taking optical system is not housed in a camera body appropriately depending upon a combination with an optical finder. It is thus likely that the camera body will be difficult to thin and downsize.
In cameras with a zoom mechanism, the picture-taking lens unit having a picture-taking optical system and the optical finder unit having a finder optical system both increase in size. Furthermore, an interlocking mechanism for interlocking the zoom operations of both the units with high precision has to be provided in order to avoid a difference in zoom ratio between the image pickup optical system and the finder optical system.
As is evident from the above, there is fear that a camera including both a picture-taking lens unit having an optical-axis bending type optical system and a zoom lens and an optical finder unit having an optical axis bending type optical system and a zoom lens can be neither compacted nor thinned.